RATE LIMITING DEVICE TO ENHANCE THE PERFORMANCE RATIO AND LONGEVITY OF A WELLBORE INFLOW CONTROL DEVICE

Abstract

An apparatus to be positioned in a wellbore formed in a subsurface formation. The apparatus comprises one or more generators disposed in a flow path within a flow control tool and configured to output electrical power to components of the flow control tool in response to flow of a fluid in the flow path, wherein the fluid enters the flow path from the wellbore. The apparatus comprises a flow rate limiting device disposed in the flow path and configured to control a flow rate of the fluid as the fluid flows to the one or more generators.

Description

FIELD

Some implementations relate generally to the field of electric downhole tools positioned in a wellbore and more particularly to the field of generating electrical power for electric downhole tools.

BACKGROUND

Tools may be positioned in a wellbore drilled in a subsurface formation to assist in controlling the flow of fluid in the wellbore. For instance, downhole tools may be utilized to control the flow of reservoir fluid as it flows from the subsurface formation to the surface. Generators may be disposed on the downhole tools to provide the downhole tools power such that the tools may function accordingly. The generators may be configured with turbines that may rotate about an axis when disposed in the path of flowing fluid produced from the subsurface formation. The generator may convert the mechanical energy of the rotating turbines to electrical energy, thus outputting electrical power to the downhole tool.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of the disclosure may be better understood by referencing the accompanying drawings.

FIG. 1 is a diagrammatic illustration of an example well system, according to some implementations.

FIG. 2 is a schematic of an example flow control tool, according to some implementations.

FIG. 3 is a chart of an example fluid flow scenario, according to some implementations.

FIG. 4 is a flowchart of example operations for controlling the flow rate to a generator of a flow control tool, according to some implementations.

DESCRIPTION

The description that follows includes example systems, methods, techniques, and program flows that embody aspects of the disclosure. However, it is understood that this disclosure may be practiced without these specific details. For instance, this disclosure refers to a flow rate limiting device and one or more generators. Aspects of this disclosure can also be applied to any other configuration of a flow rate limiting device utilized to control the flow rate to a generator. In other instances, well-known instruction instances, protocols, structures, and techniques have not been shown in detail in order not to obfuscate the description.

Example implementations relate to limiting the flow rate of a fluid to one or more turbine generators to enhance the performance ratio and longevity of a turbine based flow control tool. The flow control tool (such as an inflow control device (ICD)) may be configured with components such as electronics, a motor, valves, sensors, etc. The components of the flow control tools may require a minimum electrical power to operate. For example, the electronics may require a minimum electrical power to control the opening and/or closing of a valve to control the flow of fluid from the wellbore into a tubular string. In some implementations, flow control tools may utilize turbines of one or more generators to generate a load to power the electronics of the flow control tools. In some implementations, the one or more generators may generate electrical power via the flow of fluid interacting with the turbine of the respective generator as the fluid flows into a tubular string from the wellbore. The turbine of the generator may be required to rotate at a frequency (e.g., rotations per minute (RPM)) to generate a minimum electrical power for the electronics (i.e., just enough electrical power for the electronics to function). The RPMs of the turbine may increase as the flow rate of the fluid increases. For example, when the differential pressure across the flow control tool (e.g., between the annulus of the wellbore and the interior of the tubing string), the flow rate of fluid through the flow control tool may increase. In some implementations, excessive turbine RPM may lead to premature bearing wear, turbine wear, or other failure points within the turbine generator. Additionally, the excessive fluid flow to the turbine may result in excessive undesired fluid production. Conventional approaches may utilize a fixed nozzle disposed in line with the one or more generators. However, the fixed nozzle may result in an increase in flow rate when differential pressure increases across the system resulting in excessive turbine frequency.

In some implementations, a flow rate limiting device may be disposed in line with the generator. In some implementations, a flow control tool disposed on a tubular string may be positioned in a wellbore formed in a subsurface formation. The flow control tool may be configured to control the flow of fluid from the wellbore and into the tubular string. In some implementations, the flow control tool may include one or more generators and a flow rate limiting device. The generators may be disposed in a flow path within a flow control tool and configured to output electrical power to components of the flow control tool. For example, fluid may flow from the wellbore and through the flow path to interact with the turbines of the generators. In some implementations, a flow rate limiting device may also be disposed in the flow path (i.e., in line with the generators). The flow rate limiting device may be configured to control the flow rate of the fluid to the generators. In some implementations, the flow rate limiting device may restrict the flow rate to the turbines to a flow rate limit to generate the minimum electrical power required for the flow control device to function. For example, the generator may require a flow rate of 4 gallons per minute (GPM) to output the minimum electrical power required by the electronics to control a motor of the flow control tool. Accordingly, the flow rate limiting device may restrict the flow rate of fluid through the flow path if the flow rate is above 4.0 GPM to restrict the turbine's RPM.

In some implementations, the configuration of the generators and flow rate limiting devices may result in the ability of the flow control tool to function in high differential pressure environments due to limiting the turbine's RPM. Additionally, the turbines may be exposed to lower velocity particle impingement during high differential pressure applications which may result in an increase in the useful life of the turbines with respect to erosional wear on the blades. Moreover, the bearings may be able to be more cost effective due to the lower turbine frequencies. In some implementations, the dynamic balancing of the turbine may not be required since the frequency of the turbine may be able to be maintained lower.

Example Systems

FIG. 1 is a diagrammatic illustration of an example well system, according to some implementations. In particular, FIG. 1 is a schematic of a well system 100 that includes a wellbore 102 in a subsurface formation 101. The wellbore 102 includes casing 104 and number of perforations 114, 116 being made in the casing 104. Each set of perforations 114, 116 is located in a respective reservoir 130, 132 to allow reservoir fluids (i.e., oil, water, and gas) from the respective reservoirs 130, 132 to flow into the wellbore 102 and into the tubular string 106 (the production tubing). The tubular string 106 includes a packer 112 that may prevent the comingling of fluids produced from the reservoirs 130, 132 in the wellbore 102. A production assembly 108 may allow the inflow of fluid produced from the reservoir 130 into the tubular string 106. Likewise, a production assembly 110 may allow the inflow of fluid produced from the reservoir 132 into the tubular string 106.

The production assemblies 108, 110 may include flow control tools each configured with one or more generators and flow rate limiting devices. The inflow of fluid from the reservoirs 130, 132 to the tubular string 106 may interact with the turbines of each generator, resulting in the generation of electrical power that may be output to components of the flow control tools to control the inflow of fluid into the tubular string 106. The flow rate limiting devices may limit the flow rate to the generator turbines to prevent excessive turbine frequency, excessive undesired fluid production, etc. In some implementations, the flow control tools include an inflow control device to restrict flow as fluid flows into the tubular string 106. In some embodiments, the production assemblies 108, 110 may also include a screen.

A flowline 120 coupled to the wellhead 118 of wellbore 102 and a separator 122 may allow the fluid produced up the tubular string 106 to flow to the separator 122. The separator 122 may be designed to separate the phases of the fluid produced from the wellbore 102. For instance, oil, water, and gas may be separated from each other after passing through the separator 122. The aggregate of fluid produced from wellbore 102 may then flow to a tank battery, via flowline 124, that may include components such as storage tank 126, to store the produced fluid.

Example Flow Control Tool

Examples of a flow control tool are now described. The flow control tool is described in reference to the production assemblies 108, 110 of FIG. 1.

FIG. 2 is a schematic of an example flow control tool, according to some implementations. In particular, FIG. 2 is a schematic of a production assembly 200 (such as production assemblies 108, 110 of FIG. 1). In some implementations, the production assembly may include a flow control tool 250 disposed on a tubular string in a wellbore in a subsurface formation. The flow control tool 250 may control the flow of fluid into the tubular string to maximize hydrocarbon production (and minimize water production), control reservoir pressure, limit sand influx from the reservoir, etc. For example, the flow control tool 250 may measure the fluid density of the fluid, and control the flow of fluid into the tubular string based on the fluid density. The flow control tool 250 may be coupled with a screen 202 that may be integrated into the tubular string. Fluid may flow from the reservoir and into the wellbore. When there is a differential pressure between the wellbore and the interior of the tubular string, fluid may flow through the screen 202, pass through the flow control tool 250 via the fluid conduit 220, and enter the interior of the tubular string via a port 222. Moreover, fluid may flow to the interior of the tubing string via the flow path 204 and generator 210.

The flow control tool may be configured with any suitable components for controlling the flow of fluid into the tubular string. For instance, FIG. 2. depicts a flow control tool 250 configured with a magnet assembly to control the flow of fluid into the tubular string via the port 222. An air chamber 224 may include components such as a motor, controlled by an electronics board, and a magnet 226 and may isolate the components from the reservoir fluids. The motor may control the position of the magnet 226 relative to another magnet 228 outside of the air chamber 224. The relative positions between the magnets 226 and 228 may control the flow rate of the fluid into the tubular string via the port 222.

The electronics may be powered by a generator 210. FIG. 2 depicts one generator in flow control tool 250. The generator 210 may be configured to produce electrical power for the electronics 212. The electrical power produced by the generator 210 may depend on what the electronics require. For example, the electrical power may be between 0.1 Milliwatts (mW) to 100 Watts (W), between 1 mW and 10 W, etc. In some implementations, the flow control tool may include more than one generator 210. Multiple generators disposed in the flow path 204 may be in series or in parallel. In some implementations, the generator 210 may include a turbine generator, a vibration generator, etc., or a combination of the like. The flow path 204 may hydraulically communicate with the wellbore such that fluid may flow through the screen 202 and into the flow path 204. The flow of the fluid may enter the inlet 208 of the generator 210. The flow of the fluid may cause a turbine of the generator 210 to rotate about an axis. The rotational motion may induce a current, and the current may be output to the electronics 212 to power the electronics 212. The fluid may then continue to flow into the tubular string after interacting with the generator 210. When the generator 210 includes a vibration generator, the flow rate of the fluid through the flow path 204 may interact with components of the vibration generator and cause components to vibrate. The vibration at a certain frequency may induce a current that may be output to the electronics 212 to power the electronics 212. As shown, the generator 210 may rotate about an axis that is in the radial direction. In alternative implementations, the generator 210 may rotate about an axis that is in the axial direction or in the circumferential direction. Similarly, if the generator 210 is a vibration generator, the vibration generator may vibrate about an axis that is preferably in the axial direction but also could be in the radial or circumferential direction.

In some implementations, the flow control tool 250 may have a minimum electrical power requirement to operate. For example, the electronics 212 may require a minimum electrical power to function and subsequently control the flow of fluid into the tubular string. Any electrical power greater than the minimum electrical power may not be necessary for the electronics. For example, the excess electrical power may not be utilized by the electronics, the excess electrical power may result in shorting of the electronics, over heating of the electronics, and damage to the flow control tool, etc.

Accordingly, the generator 210 may have a flow rate limit which may correlate to the minimum electrical power requirement of the flow control tool. For example, the flow rate limit may be the flow rate at which the generator 210 outputs an electrical power similar to the minimum electrical power of the electronics. In some implementations, the flow rate limit may correspond to an electrical power output that is approximately equal to or greater than the minimum electrical power. For instance, the flow rate limit may be set such that when the flow rate through the flow path 204 is at the flow rate limit, the electrical power generated by the generator 210 is 5% above the minimum electrical power required by the electronics 212.

In addition to meeting the minimum electrical power required by the electronics 212, the flow rate limit may be in place to protect the components of the generator 210 (such as the turbines, bearings, etc.) from getting damaged. Additionally, the flow rate limit may prevent excessive undesired fluid production (such as water). For example, differential pressure across the flow control tool 250 may increase upon water breakthrough due to the higher mobility of water through the formation. The flow control tool 250 may restrict the flow of the fluid through the port 222 to reduce water production. Additionally, the increased differential pressure may result in a higher flow rate through the flow path 204 and into the tubular string, resulting in an increase in water production. The flow rate limit may restrict the flow of water through the flow path 204 and into the tubular string, reducing undesired fluid production.

To maintain the flow rate limit, a flow rate limiting device 206 may be disposed in the flow path 204. The flow rate limiting device may be a spring-based device configured to self-regulate the flow rate of the fluid in the flow path 204. For example, the flow rate limiting device 206 may be configured with a spring that may be calibrated to open or close a valve within the flow rate limiting device 206 based on the flow rate of the fluid in the flow path 204. The spring may include one or more mechanical springs (such as a coil spring, wave spring, Belville spring, etc.) a fluid spring (such as compressed nitrogen), etc. Any other suitable components configured to limit the flow of a fluid may be utilized as the flow rate limiting device 206 to control the flow rate to the generator 210. In some implementations, the flow rate limiting device 206 may be proximate the inlet or outlet of the generator 210 (i.e., upstream or downstream of the generator 210). The flow rate limiting device 206 may be configured to restrict the flow rate to the generator 210, regardless of the differential pressures across the flow control tool 250, such that the flow rate to the generator 210 is less than or equal to the flow rate limit. For example, if the flow rate limit is 4 gallons per minute (GPM), then the flow rate limiting device 206 may restrict the flow rate in the flow path 204 if the flow rate exceeds 4 GPM, such that the generator may only be exposed to a flow rate of 4 GPM or less. If the differential pressure remains constant and/or varies (such as when different fluid phases enter the wellbore), the flow rate limiting device 206 may maintain the flow rate limit of 4 GPM to the generator 210.

In some implementations, the flow limiting restriction may be configured to provide variable restriction over a predetermined range of flow rates. For example, the flow rate limiting device 206 may provide a fixed flow restriction until an initial closing rate is achieved (a first threshold rate). Above that initial closing rate, increasing restriction is applied with increasing flow rate until a final closing rate may be achieved (a second threshold rate). Above the final closing rate, the flow limiting device 206 provides a second fixed flow restriction.

In some implementations, the flow rate limit of the generator 210 and of the flow rate limiting device 206 may be different in different fluids. For example, a flow rate limit of 4 GPM may be needed by the generator 210 when the fluid is oil and a different flow rate limit of 20 GPM may be needed by the generator 210 when the fluid is gas due to the lower density and/or viscosity of gas. In other applications, the flow rate limiting device 206 may maintain a constant pressure acting on the generator 210.

To help illustrate, FIG. 3 is a chart of an example fluid flow scenario, according to some implementations. In particular, FIG. 3 includes a chart 300 with an x-axis 302 and a y-axis 304. The x-axis 302 is the differential pressure having units in pounds per square inch (PSI). The y-axis 304 is the flow rate having units in gallons per minute (GPM). The chart 300 depicts two scenarios. The first being how the flow rate reacts when a fixed orifice is disposed in a flow path for a generator (such as flow path 204 of FIG. 2). The second being how the flow rate reacts when a flow rate limiting device (such as flow rate limiting device 206 of FIG. 2) configured to maintain a flow rate limit of 4 GPM or less is disposed in a flow path for a generator. As shown, the fixed orifice curve 306 depicts how the flow rate continuously increased as differential pressure increases. Alternatively, the flow rate limiting device curve depicts that the flow rate is restricted to 4 GPM as the differential pressure increases.

Returning to FIG. 2, the flow rate limiting device 206 depicted in FIG. 2 includes a pressure restricting restrictor. A pressure restricting restrictor may increase the restriction of the flow rate to the generator 210 when the differential pressure across the flow control tool 250 increased and/or the flow rate through the flow path 204 increases. In some implementations, the flow rate limiting device 206 may be a pressure loosening restrictor. The pressure loosening restrictor may decrease the restriction of the flow rate to the generator 210 when the differential pressure across the flow control tool 250 increases and/or the flow rate through the flow path 204 increases. Any suitable configuration of flow restriction may be utilized in the flow rate limiting device 206 to control the flow rate to the generator 210.

Example Operations

Example operations for outputting electrical power to components of a flow control tool are now described in reference to FIG. 2.

FIG. 4 is a flowchart of example operations for controlling the flow rate to a generator of a flow control tool, according to some implementations. FIG. 4 depicts a flowchart 400 of operations to output electrical power, via one or more generators, to components of a flow control tool to control the flow of fluid into a tubular string. The operations of flowchart 400 are described in reference to flow control tools included in production assemblies 108, 110 of FIG. 1 and production assembly 200 of FIG. 2.

At block 402, a flow rate limiting device disposed in a flow path within a flow control tool positioned in a wellbore formed in a subsurface formation may control the flow rate of a fluid to one or more generators as the fluid flows through the flow path.

At block 404, the one or more generators disposed in the flow path may output electrical power to components of the flow control tool in response to the flow rate of the fluid as the fluid flows through the flow path.

Example Implementations

Implementation #1: An apparatus to be positioned in a wellbore formed in a subsurface formation, the apparatus comprising: one or more generators disposed in a flow path within a flow control tool and configured to output electrical power to components of the flow control tool in response to flow of a fluid in the flow path, wherein the fluid enters the flow path from the wellbore; and a flow rate limiting device disposed in the flow path and configured to control a flow rate of the fluid as the fluid flows to the one or more generators.

Implementation #2: The apparatus of Implementation #1, wherein the flow rate limiting device is proximate an inlet or an outlet of the one or more generators.

Implementation #3: The apparatus of Implementation #1 or #2, wherein the one or more generators includes a turbine generator or a vibration generator.

Implementation #4: The apparatus of any one or more of Implementations #1-3, wherein the components of the flow control tool include electronics, powered by the one or more generators, to control the flow of the fluid into a tubular string.

Implementation #5: The apparatus of Implementation #4, wherein the electronics of the flow control tool require a minimum electrical power to control the flow of the fluid into the tubular string, and wherein the one or more generators are configured to generate the minimum electrical power based on a flow rate limit of the fluid in the flow path.

Implementation #6: The apparatus of Implementation #5, wherein the flow rate limiting device is configured to restrict the flow rate of the fluid in the flow path to the one or more generators when the flow rate is greater than the flow rate limit.

Implementation #7: The apparatus of any one or more of Implementations #1-6, wherein the flow rate limiting device is a spring-based device.

Implementation #8: The apparatus of Implementation #7, wherein the spring-based device includes a mechanical spring or a fluid spring.

Implementation #9: A system comprising: a tubular string to be positioned in a wellbore formed in a subsurface formation; and a flow control tool disposed on the tubular string, the flow control tool comprising, one or more generators positioned in a flow path within the flow control tool and configured to output electrical power to components the flow control tool in response to flow of a fluid in the flow path, wherein the fluid enters the flow path from the wellbore, and a flow rate limiting device positioned in the flow path and configured to control a flow rate of the fluid as the fluid flows to the one or more generators.

Implementation #10: The system of Implementation #9, wherein the flow rate limiting device is proximate an inlet or outlet of the one or more generators.

Implementation #11: The system of Implementation #9 or #10, the one or more generators includes a turbine generator and a vibration generator.

Implementation #12: The system of any one or more of Implementations #9-11, wherein the components of the flow control tool include electronics powered by the one or more generators to control the flow of the fluid into the tubular string.

Implementation #13: The system of Implementation #12, wherein the electronics of the flow control tool require a minimum electrical power to control the flow of the fluid into the tubular string, and wherein the one or more generators are configured to generate the minimum electrical power based on a flow rate limit.

Implementation #14: The system of Implementation #13, wherein the flow rate limiting device is configured to restrict the flow rate of the fluid to the one or more generators when the flow rate is greater than the flow rate limit.

Implementation #15: The system of any one or more of Implementations #9-14, wherein the flow rate limiting device is configured to self-regulate the flow rate of the fluid in the flow path.

Implementation #16: A method comprising: controlling, via a flow rate limiting device disposed in a flow path within a flow control tool positioned in a wellbore formed in a subsurface formation, a flow rate of a fluid to one or more generators as the fluid flows through the flow path; outputting, via the one or more generators disposed in the flow path, electrical power to components of the flow control tool in response to the flow rate of the fluid as the fluid flows through the flow path.

Implementation #17: The method of Implementation #16, wherein the flow rate limiting device is proximate an inlet or outlet of the one or more generators.

Implementation #18: The method of Implementation #16 or #17, wherein the components of the flow control tool include electronics powered by the one or more generators to control flow of the fluid into a tubular string.

Implementation #19: The method of Implementation #18, wherein the electronics of the flow control tool require a minimum electrical power to control the flow of the fluid into the tubular string, and wherein the one or more generators are configured to generate the minimum electrical power based on a flow rate limit.

Implementation #20: The method of Implementation #19, wherein the flow rate limiting device is configured to restrict the flow rate of the fluid to the one or more generators when the flow rate is greater than the flow rate limit.

Use of the phrase “at least one of” preceding a list with the conjunction “and” should not be treated as an exclusive list and should not be construed as a list of categories with one item from each category, unless specifically stated otherwise. A clause that recites “at least one of A, B, and C” can be infringed with only one of the listed items, multiple of the listed items, and one or more of the items in the list and another item not listed.

As used herein, the term “or” is inclusive unless otherwise explicitly noted. Thus, the phrase “at least one of A, B, or C” is satisfied by any element from the set {A, B, C} or any combination thereof, including multiples of any element.

Claims

1. An apparatus to be positioned in a wellbore formed in a subsurface formation, the apparatus comprising: one or more generators disposed in a flow path within a flow control tool and configured to output electrical power to components of the flow control tool in response to flow of a fluid in the flow path, wherein the fluid enters the flow path from the wellbore; anda flow rate limiting device disposed in the flow path and configured to control a flow rate of the fluid as the fluid flows to the one or more generators.

2. The apparatus of claim 1, wherein the flow rate limiting device is proximate an inlet or an outlet of the one or more generators.

3. The apparatus of claim 1, wherein the one or more generators includes a turbine generator or a vibration generator.

4. The apparatus of claim 1, wherein the components of the flow control tool include electronics, powered by the one or more generators, to control the flow of the fluid into a tubular string.

5. The apparatus of claim 4, wherein the electronics of the flow control tool require a minimum electrical power to control the flow of the fluid into the tubular string, and wherein the one or more generators are configured to generate the minimum electrical power based on a flow rate limit of the fluid in the flow path.

6. The apparatus of claim 5, wherein the flow rate limiting device is configured to restrict the flow rate of the fluid in the flow path to the one or more generators when the flow rate is greater than the flow rate limit.

7. The apparatus of claim 1, wherein the flow rate limiting device is a spring-based device.

8. The apparatus of claim 7, wherein the spring-based device includes a mechanical spring or a fluid spring.

9. A system comprising: a tubular string to be positioned in a wellbore formed in a subsurface formation; anda flow control tool disposed on the tubular string, the flow control tool comprising, one or more generators positioned in a flow path within the flow control tool and configured to output electrical power to components the flow control tool in response to flow of a fluid in the flow path, wherein the fluid enters the flow path from the wellbore, anda flow rate limiting device positioned in the flow path and configured to control a flow rate of the fluid as the fluid flows to the one or more generators.

10. The system of claim 9, wherein the flow rate limiting device is proximate an inlet or outlet of the one or more generators.

11. The system of claim 9, the one or more generators includes a turbine generator and a vibration generator.

12. The system of claim 9, wherein the components of the flow control tool include electronics powered by the one or more generators to control the flow of the fluid into the tubular string.

13. The system of claim 12, wherein the electronics of the flow control tool require a minimum electrical power to control the flow of the fluid into the tubular string, and wherein the one or more generators are configured to generate the minimum electrical power based on a flow rate limit.

14. The system of claim 13, wherein the flow rate limiting device is configured to restrict the flow rate of the fluid to the one or more generators when the flow rate is greater than the flow rate limit.

15. The system of claim 9, wherein the flow rate limiting device is configured to self-regulate the flow rate of the fluid in the flow path.

16. A method comprising: controlling, via a flow rate limiting device disposed in a flow path within a flow control tool positioned in a wellbore formed in a subsurface formation, a flow rate of a fluid to one or more generators as the fluid flows through the flow path;outputting, via the one or more generators disposed in the flow path, electrical power to components of the flow control tool in response to the flow rate of the fluid as the fluid flows through the flow path.

17. The method of claim 16, wherein the flow rate limiting device is proximate an inlet or outlet of the one or more generators.

18. The method of claim 16, wherein the components of the flow control tool include electronics powered by the one or more generators to control flow of the fluid into a tubular string.

19. The method of claim 18, wherein the electronics of the flow control tool require a minimum electrical power to control the flow of the fluid into the tubular string, and wherein the one or more generators are configured to generate the minimum electrical power based on a flow rate limit.

20. The method of claim 19, wherein the flow rate limiting device is configured to restrict the flow rate of the fluid to the one or more generators when the flow rate is greater than the flow rate limit.